<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
		<style type="text/css">
			*{
				padding: 0;
				margin: 0;
			}
			.container {
				width: 100vw;
				height: 100vh;
				display: flex;
				align-items: center;
				justify-content: center;
			}
			canvas {
				width: 500px;
				height: 500px;
				border: 2px solid blue;
			}
		</style>
	</head>
	<body>
		<div id="answer"></div>
		<div class="container">
			<canvas id="canvas" width="500" height="500"></canvas>
		</div>
	</body>
		<script type="text/javascript">
			window.onload=function(){
				var oAnswer = document.getElementById("answer");
				let n = 10;
				let str = "";
				for (var i =0;i<n;i++) {
					for (var j =0;j<=i;j++) {
					   str+="*";
					}
					str +="</br>";
					str+="\n";
				}
				oAnswer.innerHTML=str;
				console.log(str);
				
				let oCanvas = document.getElementById('canvas');
			
			    console.dir(oCanvas);
			
			    let oPen = oCanvas.getContext("2d");
			
			    console.dir(oPen);
			}
		</script>
	</body>
</html>
